[MIPS] Fix BUG(), BUG_ON() handling

With commit 63dc68a8cf60cb110b147dab1704d990808b39e2, kernel can not
handle BUG() and BUG_ON() properly since get_user() returns false for
kernel code.  Use __get_user() to skip unnecessary access_ok().  This
patch also make BRK_BUG code encoded in the TNE instruction.

Signed-off-by: Atsushi Nemoto <anemo@mba.ocn.ne.jp>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

2 files changed, 4 insertions, 3 deletions

diff --git a/arch/mips/kernel/traps.c b/arch/mips/kernel/traps.c
index 6b356f62289e..493cb29b8a42 100644
--- a/arch/mips/kernel/traps.c
+++ b/arch/mips/kernel/traps.c
@@ -650,7 +650,7 @@ asmlinkage void do_bp(struct pt_regs *regs)
         unsigned int opcode, bcode;
         siginfo_t info;
 
-        if (get_user(opcode, (unsigned int __user *) exception_epc(regs)))
+        if (__get_user(opcode, (unsigned int __user *) exception_epc(regs)))
                 goto out_sigsegv;
 
         /*
@@ -700,7 +700,7 @@ asmlinkage void do_tr(struct pt_regs *regs)
         unsigned int opcode, tcode = 0;
         siginfo_t info;
 
-        if (get_user(opcode, (unsigned int __user *) exception_epc(regs)))
+        if (__get_user(opcode, (unsigned int __user *) exception_epc(regs)))
                 goto out_sigsegv;
 
         /* Immediate versions don't provide a code.  */
diff --git a/include/asm-mips/bug.h b/include/asm-mips/bug.h
index 4d560a533940..7eb63de808bc 100644
--- a/include/asm-mips/bug.h
+++ b/include/asm-mips/bug.h
@@ -18,7 +18,8 @@ do {									\
 
 #define BUG_ON(condition)                                               \
 do {                                                                    \
-        __asm__ __volatile__("tne $0, %0" : : "r" (condition));         \
+        __asm__ __volatile__("tne $0, %0, %1"                           \
+                             : : "r" (condition), "i" (BRK_BUG));       \
 } while (0)
 
 #define HAVE_ARCH_BUG_ON